How much solar power can my location generate?
The most useful number for comparing places is kWh/kWp/year: how many kilowatt-hours of electricity one kilowatt-peak (kWp) of solar panels produces in a typical year. A “5 kW” rooftop system is 5 kWp, so multiply the map value by 5. A place scoring 1,000 kWh/kWp/year would give a 5 kW system about 5,000 kWh a year; a place scoring 1,600 would give about 8,000 kWh.
SolarMapped colours the whole map by this value for fixed panels tilted at their best angle. Click anywhere on land for the local figure, the month-by-month pattern and the best tilt.
| City | kWh per kWp per year | 5 kW system, per year |
|---|---|---|
| Helsinki, Finland | ≈ 970 | ≈ 4,900 kWh |
| Berlin, Germany | ≈ 1,050 | ≈ 5,300 kWh |
| New York, United States | ≈ 1,400 | ≈ 7,000 kWh |
| Madrid, Spain | ≈ 1,620 | ≈ 8,100 kWh |
| Sydney, Australia | ≈ 1,580 | ≈ 7,900 kWh |
| Cairo, Egypt | ≈ 1,820 | ≈ 9,100 kWh |
Example PVGIS values, rounded, for crystalline-silicon panels at their optimal fixed tilt facing the equator, with 14% system losses. Click any city on the map for the exact current figure.
What is solar potential?
People use “solar potential” for two different things. Solar irradiation (or radiation) is the sunlight energy that reaches a surface, measured in kWh per square metre. PV output is the electricity a solar system actually produces from that light, in kWh per kWp.
PV output is the more practical measure. Panels lose efficiency when they get hot, reflect some light at low angles and pass energy through cables and inverters, so output isn’t simply proportional to irradiation. SolarMapped therefore leads with PV output and shows irradiation as a secondary figure.
How does location affect solar panel production?
- Latitude. Closer to the equator the sun is higher and the year more even. Far from it, winters are dark and production is concentrated in summer.
- Cloud cover and climate. Cloudy, humid regions get less direct sun than dry ones at the same latitude, which is why deserts lead the map.
- Temperature. Solar panels are slightly less efficient when hot, so a very hot site loses some of its advantage.
- Tilt and orientation. Fixed panels do best facing the equator (south in the northern hemisphere, north in the southern) at an angle close to the latitude, flatter near the equator.
- Shading. Hills on the horizon are modelled where data exists; nearby buildings and trees are not, and they matter a lot on real roofs.
How SolarMapped calculates solar production
The map layer and the per-location report both come from PVGIS, the free Photovoltaic Geographical Information System from the European Commission’s Joint Research Centre. The map was pre-computed on a 2° global grid and smoothed; the report on the right runs a fresh PVGIS calculation for the exact spot you pick (rounded to about one kilometre) and caches it.
Assumptions: crystalline-silicon panels, 14% system losses, fixed free-standing mounting facing the equator, tilt optimised for the location, and terrain horizon shading where available. Changing system size scales the result directly. Real systems vary with panel quality, roof shape, shading, dirt and snow, and year-to-year weather. See Sources and method for the details and data licences.
Solar potential by location
Country and city pages with location-specific solar data are coming. Until then, use the search box above to look up any city.